Osaka Purple Mustard
Brassica juncea 'Osaka Purple'
A stunning Japanese mustard green with deep purple leaves and bright green stems that creates an eye-catching contrast in any garden bed or salad bowl. This fast-growing beauty offers a mild mustard flavor when young that intensifies as leaves mature, giving you versatility from baby greens to cooking greens.
Harvest
21-40d
Days to harvest
Sun
Full sun to partial shade
Zones
8–9
USDA hardiness
Height
12-18 inches
Planting Timeline
Showing dates for Osaka Purple Mustard in USDA Zone 7
All Zone 7 brassica →Zone Map
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Osaka Purple Mustard · Zones 8–9
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | March – April | May – June | May – June | June – October |
| Zone 4 | March – April | May – June | April – June | May – October |
| Zone 5 | February – March | April – May | April – May | May – November |
| Zone 6 | February – March | April – May | April – May | May – November |
| Zone 7 | February – March | April – May | March – May | April – November |
| Zone 8 | January – February | March – April | March – April | April – December |
| Zone 9 | January – January | February – March | February – March | March – December |
| Zone 10 | January – January | February – March | January – March | February – December |
Complete Growing Guide
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: High Organic Matter. Soil pH: Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Water: Davidson County Extension Demonstration Garden. Height: 1 ft. 0 in. - 1 ft. 6 in.. Spread: 1 ft. 0 in. - 1 ft. 6 in.. Spacing: Less than 12 inches. Growth rate: Rapid. Maintenance: Medium. Regions: Coastal, Mountains, Piedmont.
Harvesting
Long pods with round, brown seeds. The fruits will dry and split when ripe. The seeds are harvested for use in condiments and oil.
Color: Brown/Copper. Type: Siliqua.
Garden value: Edible
Bloom time: Fall, Summer
Edibility: The leaves, seeds, flowers, and stems of this mustard variety are edible raw or cooked. Harvested leaves can be stored in the fridge for 3-5 days.
Storage & Preservation
Fresh Osaka Purple Mustard leaves store best when harvested dry and immediately refrigerated. Wrap unwashed leaves loosely in damp paper towels, then place in perforated plastic bags in your refrigerator's crisper drawer. Properly stored, young leaves maintain quality for 5-7 days, while mature leaves last 3-4 days.
For preservation, blanch leaves in boiling water for 2 minutes, then shock in ice water before freezing in airtight containers—this method preserves both color and nutritional value for up to 8 months. The deep purple leaves also make stunning additions to lacto-fermented vegetable mixes, maintaining their vibrant color while developing complex flavors.
Dehydrating works well for mature leaves; dried Osaka Purple Mustard creates an attractive purple seasoning powder perfect for spice blends. Young tender leaves can be preserved in herb salt or frozen directly into ice cubes for adding to soups and stews during winter months.
History & Origin
Origin: Russia to central Asia
Advantages
- +Attracts: The leaves, seeds, flowers, and stems of this mustard variety are edible raw or cooked. Harvested leaves can be stored in the fridge for 3-5 days.
- +Wildlife value: Bees are attracted.
- +Edible: The leaves, seeds, flowers, and stems of this mustard variety are edible raw or cooked. Harvested leaves can be stored in the fridge for 3-5 days.
- +Fast-growing
Companion Plants
Plant Together
Nasturtiums
Act as trap crops for flea beetles and aphids that commonly attack brassicas
Dill
Attracts beneficial insects like parasitic wasps that control cabbage worms and aphids
Onions
Repel cabbage maggots and other root pests with their strong sulfur compounds
Garlic
Deters flea beetles and cabbage worms while improving soil health
Marigolds
Repel nematodes and various pests while attracting beneficial predatory insects
Lettuce
Makes efficient use of space as a low-growing companion and has similar water needs
Carrots
Help break up soil for shallow brassica roots and don't compete for nutrients
Chives
Repel aphids and improve growth of neighboring brassicas through root secretions
Keep Apart
Strawberries
Compete for similar nutrients and can harbor pests that also attack brassicas
Tomatoes
Both are heavy feeders that compete for nutrients, and tomatoes can stunt brassica growth
Pole Beans
Can shade the mustard greens excessively and compete for root space
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #747447)
Pests & Disease Resistance
Resistance
Good bolt resistance in cool weather
Common Pests
Flea beetles, aphids, cabbage worms
Diseases
Downy mildew, white rust, black rot